The Cabinet is to veto the publication of an internal risk assessment of the Government's contentious NHS reforms, it was announced today.

The move to defy a ruling by the Information Tribunal that the risk register should be released under the Freedom of Information Act was agreed by the full Cabinet.

Andrew Lansley, the Health Secretary said the decision to exercise the veto had been taken to protect the “safe space where officials are able to give ministers full and frank advice in developing policies and programmes”.

However the move was condemned by Labour which described it as “poor policy and dumb politics”, which would “fuel doubts and distrust” about the health reforms.

The November 2010 risk register for the Health and Social Care Act reforms, which became law in March, was requested by Labour MP John Healey.

Drawn up by civil servants it is believed to describe the potential risks attached to each area of the reform programme.

Information Commissioner Christopher Graham agreed that the documents should be published and, after an appeal by the Department of Health, the Information Tribunal also ruled for disclosure.

But the Cabinet agreed today that the “ministerial veto” should be used to prevent publication.

The veto is used very rarely - the last time it was used was when the Labour government vetoed the release of Cabinet minutes relating to the invasion of Iraq.

Mr Lansley said he was instead publishing a document setting out “key information” from the register but protecting its “language and form”.

“Had we not taken this decision, it is highly likely that future sensitive risk registers would turn into anodyne documents, and be worded quite differently with civil servants worrying about how they sound to the public rather than giving ministers frank policy advice,” he said in a statement.

Mr Healey described the decision as a “desperate act” which would backfire.

“It is an admission of defeat on the legal arguments for public release,” he said.

"It is totally over the top to place NHS changes on the same footing as preparations for the Iraq war.

"There must be some very big risks in the Government's NHS reorganisation for ministers to override the law with their political veto.

"Ministers have made the announcement in the very last hour of the last day, trying to bury this bad news on the eve of the Queen's Speech.

"The Government has lost twice in law, yet still won't accept that patients and NHS staff have the right to know the risks ministers are running with the biggest-ever NHS reorganisation."